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a)
204-84:12
=204-7
=197
b)
15.23+4.32-5.7
=15.8+4.9-5.7
=120+36-35
=156-35
=121
c)
56:53+23.22
=56-3+23+2
=53+25
=125+32
=157
d)
164.53+47.164
=(164.(53+47)
=164.100
=16400
tìm x:
219-7(x+1)=100
=>7(x+1)=219-100
=>7(x+1)=119
=>x+1=119:7
=>x+1=17
=>x=17-1
=>x=16
(3x-6).3=34
=>(3x-6).3=81
=>3x-6=81:3
=>3x-6=27
=>3x=27+6
=>3x=33
=>x=33:3
=>x=11
a)
204 - 84:12 = 204 - 7 = 197
b)
15.23 + 4.32 - 5.7 = 15.8 + 4.9 – 5.7 = 120 + 36 - 35 = 121
c) Áp dụng:
am . an = am+n
am : an = am-n
56:53 + 23.22 = 53 + 25 = 125 + 32 = 157
d)
164.53 + 47.164 = 164(53 + 47) = 164.100 = 16400
a) 204 - 84 : 12
= 204 - 7 = 197
b) 15.23 + 4.32 - 5.7
= 15.8 + 4.9 - 35
= 120 + 36 - 35
= 156 - 35
= 121
c) 56 : 53 + 23.22
= 56 - 3 + 23 + 2
= 53 + 25
= 125 + 32
= 157
d) 164.53 + 47.164
= 164.( 53 + 47 )
= 164.100
= 16400
204-84:2=204-42=162
15.23+4.32-5.7=15.8+4.9-35=120+36-35=121
56:53+23.22=15625:125+8.4=125+32=157
164.53+47.164=164.(53+47)=164.100=16400
HỌC TỐT.
a , 3x - 4 = 57 : 56
3x - 4 = 57-6
3x -4 = 5
3x = 9
3x = 32
suy ra x = 2
Vậy x =2
b , 3x-1 = 27
3x-1 = 33
suy ra x - 1 =3 suy ra x = 3-1 =2
Vậy x =2
c , (x-1)3 = 4(x-1)
( x - 1)3 : ( x-1 ) = 4
(x-1)3-1 = 4
(x-1)2 = 22
suy ra x-1 =2 suy ra x = 2+1 =3
Vậy x =3
d , 5x . 5x-2 = 130
5x . 5x : 52 = 130
52x = 130 x 25
52s = 3250
suy ra x thuộc rỗng
Vậy x thuộc rỗng
a) 3^x -4 =5^7 : 5^6
3^x -4 =5
3^x=9
x=2
b ) 3^x-1=26
3^x=27
x=3
a) \(204-84:12=204-7=197\)
b) \(15.2^3+4.3^2-5.7=15.8+4.9+5.7=120+36+35=156+35=191\)
c) \(5^6:5^3+2^3.2^2=5^3+2^5=125+32=157\)
d) \(164.53+47.164=164.\left(53+47\right)=164.100=16400\)
_Chúc bạn học tốt_
toi nay mk se lay y kien cua cac ban , giup mk nha
b1
a) \(\dfrac{1}{5.6}+\dfrac{1}{6.7}+\dfrac{1}{7.8}+\dfrac{1}{8.9}+\dfrac{1}{9.10}\)
\(=\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{10}\)
\(=\dfrac{1}{5}-\dfrac{1}{10}\)
\(=\dfrac{2}{10}-\dfrac{1}{10}\)
\(=\dfrac{1}{10}\)
b) \(\dfrac{1}{1.2}+\dfrac{1}{2.3}+...+\dfrac{1}{99.100}\)
\(=\dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{99}-\dfrac{1}{100}\)
\(=\dfrac{1}{1}-\dfrac{1}{100}\)
\(=\dfrac{99}{100}\)
c) \(\dfrac{2}{3.5}+\dfrac{2}{5.7}+\dfrac{2}{7.9}+\dfrac{2}{9.11}\)
\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{11}\)
\(=\dfrac{1}{3}-\dfrac{1}{11}\)
\(=\dfrac{8}{33}\)
d) \(\dfrac{2}{3.5}+\dfrac{2}{5.7}+...+\dfrac{2}{99.101}\)
\(=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+...+\dfrac{1}{99}-\dfrac{1}{101}\)
\(=\dfrac{1}{3}-\dfrac{1}{101}\)
\(=\dfrac{98}{303}\)
a) 204 - 84 : 12 = 204 - 7 = 197
b) 15.23 + 4 . 32 - 5.7 = 15 . 8 + 4 . 9 - 5 . 7 = 120 + 36 - 35 = 121
c) 56 : 53 + 23 . 22 = 15625 : 125 + 8 . 4 = 125 + 32 = 157
d) 164 . 53 + 47 x 164 = 164 x ( 53 + 47 ) = 164 x 100 = 16400
a) x + \(\frac{1}{6}\)=\(-\frac{3}{8}\)
x=\(\frac{-3}{8}-\frac{1}{6}\)
x=\(\frac{-13}{24}\)
b)\(\frac{1}{2}\)x + \(\frac{1}{8}\)x = \(\frac{3}{4}\)
\(\left(\frac{1}{2}+\frac{1}{8}\right)\)x = \(\frac{3}{4}\)
\(\frac{5}{8}\)x = \(\frac{3}{4}\)
x = \(\frac{3}{4}:\frac{5}{8}\)
x =\(\frac{6}{5}\)
c) 2 - l3/4-xl=7/12
l3/4-xl=17/12
nếu 3/4 - x > 0
thì 3/4 - x = 17/12
x= -2/3
nếu 3/4 - x <0
thì 3/4 - x = -17/12
x = 13/6
d) \(\left(2x-4.5\right):\frac{3}{4}-\frac{1}{3}=1\)
\(\left(2x-4.5\right):\frac{3}{4}=\frac{4}{3}\)
\(2x-4.5=1\)
2x = 5.5
x = 2.75
a, x + 1/6 = -3/8
x = -3/8 - 1/6
x = -13/24
b, 1/2x + 1/8x = 3/4
x * (1/2+1/8) = 3/4
x * 5/8 = 3/4
x = 3/4 : 5/8
x = 6/5
c, 2 - |3/4-x| = 7/12
|3/4-x| = 2 - 7/12
|3/4-x| = 17/12
=> 3/4 - x = 17/12 hoặc -17/12
# 3/4 - x = 17/12
=> x = -2/3
# 3/4 - x = -17/12
=> x = 13/6
=> x = { -2/3 ; 13/6}
d, (2x - 4,5) : 3/4 -1/3 = 1
(2x - 4,5) : 3/4 = 1 + 1/3
(2x - 4,5 ) : 3/4 = 4/3
2x - 4,5 = 4/3 * 3/4
2x - 4,5 = 1
2x = 1 + 4,5
2x = 5,5
x = 5,5 : 2
x = 2,75
a, 204 - 84.12
= 12.17 - 12.84
= 12 . (17-84)
= 12 . (-67)
= -804
b, 15.23 + 4.32 - 5.7
= 15.8 + 4.9 - 5.7
= 120 + 36 - 35
= 120 +1
= 121
c, 56 : 53 + 23 . 22
= 56-3 + 23+2
= 53 + 25
= 125 - 32
= 93
d, 164.53 + 47.164
= 164.(53 + 47)
= 164 . 100
= 16400
Vậy ...
Nhớ line cho mình nhé!